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;;; eq.scm -- An equation formatting package.
;;;
;;; Copyright 2005, 2006 Ludovic Court�s <ludovic.courtes@laas.fr>
;;;
;;;
;;; This program is free software; you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 2 of the License, or
;;; (at your option) any later version.
;;;
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program; if not, write to the Free Software
;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
;;; USA.
(define-module (skribilo package eq)
:autoload (skribilo ast) (markup?)
:autoload (skribilo output) (output)
:use-module (skribilo writer)
:use-module (skribilo engine)
:use-module (skribilo lib)
:use-module (skribilo utils syntax)
:use-module (skribilo module)
:use-module (skribilo skribe utils) ;; `the-options', etc.
:use-module (ice-9 optargs))
;;; Author: Ludovic Court�s
;;;
;;; Commentary:
;;;
;;; This package defines a set of markups for formatting equations. The user
;;; may either use the standard Scheme prefix notation to represent
;;; equations, or directly use the specific markups (which looks more
;;; verbose).
;;;
;;; FIXME: This is incomplete.
;;;
;;; Code:
(fluid-set! current-reader %skribilo-module-reader)
;;;
;;; Utilities.
;;;
(define %operators
'(/ * + - = != ~= < > <= >= sqrt expt sum product script))
(define %rebindings
(map (lambda (sym)
(list sym (symbol-append 'eq: sym)))
%operators))
(define (eq:symbols->strings equation)
"Turn symbols located in non-@code{car} positions into strings."
(cond ((list? equation)
(if (or (null? equation) (null? (cdr equation)))
equation
(cons (car equation) ;; XXX: not tail-recursive
(map eq:symbols->strings (cdr equation)))))
((symbol? equation)
(symbol->string equation))
(else equation)))
(define-public (eq-evaluate equation)
"Evaluate @var{equation}, an sexp (list) representing an equation, e.g.
@code{'(+ a (/ b 3))}."
(eval `(let ,%rebindings ,(eq:symbols->strings equation))
(current-module)))
;;;
;;; Markup.
;;;
(define-markup (eq :rest opts :key (ident #f) (class "eq"))
(new markup
(markup 'eq)
(ident (or ident (symbol->string (gensym "eq"))))
(options (the-options opts))
(body (let loop ((body (the-body opts))
(result '()))
(if (null? body)
result
(loop (cdr body)
(if (markup? (car body))
(car body) ;; the `eq:*' markups were used
;; directly
(eq-evaluate (car body))) ;; a quoted list was
;; passed
))))))
(define-simple-markup eq:/)
(define-simple-markup eq:*)
(define-simple-markup eq:+)
(define-simple-markup eq:-)
(define-simple-markup eq:=)
(define-simple-markup eq:!=)
(define-simple-markup eq:~=)
(define-simple-markup eq:<)
(define-simple-markup eq:>)
(define-simple-markup eq:>=)
(define-simple-markup eq:<=)
(define-simple-markup eq:sqrt)
(define-simple-markup eq:expt)
(define-markup (eq:sum :rest opts :key (ident #f) (class "eq:sum")
(from #f) (to #f))
(new markup
(markup 'eq:sum)
(ident (or ident (symbol->string (gensym "eq:sum"))))
(options (the-options opts))
(body (the-body opts))))
(define-markup (eq:product :rest opts :key (ident #f) (class "eq:product")
(from #f) (to #f))
(new markup
(markup 'eq:product)
(ident (or ident (symbol->string (gensym "eq:product"))))
(options (the-options opts))
(body (the-body opts))))
(define-markup (eq:script :rest opts :key (ident #f) (class "eq:script")
(sub #f) (sup #f))
(new markup
(markup 'eq:script)
(ident (or ident (symbol->string (gensym "eq:script"))))
(options (the-options opts))
(body (the-body opts))))
;;;
;;; Lout implementation
;;;
(let ((lout (find-engine 'lout)))
(if (not lout)
(skribe-error 'eq "Lout engine not found" lout)
(let ((includes (engine-custom lout 'includes)))
;; Append the `eq' include file
(engine-custom-set! lout 'includes
(string-append includes "\n"
"@SysInclude { eq }\n")))))
;; FIXME: Reimplement the `symbol' writer so that `@Sym' is not used within
;; equations (e.g. output `alpha' instead of `{ @Sym alpha }').
(markup-writer 'eq (find-engine 'lout)
:before "\n@Eq { "
:action (lambda (node engine)
(let ((eq (markup-body node)))
;(fprint (current-error-port) "eq=" eq)
(output eq engine)))
:after " }\n")
;;
;; `+' and `-' have lower precedence than `*', `/', `=', etc., so their
;; operands do not need to be enclosed in braces.
;;
(markup-writer 'eq:+ (find-engine 'lout)
:action (lambda (node engine)
(let loop ((operands (markup-body node)))
(if (null? operands)
#t
(begin
;; no braces
(output (car operands) engine)
(if (pair? (cdr operands))
(display " + "))
(loop (cdr operands)))))))
(markup-writer 'eq:- (find-engine 'lout)
:action (lambda (node engine)
(let loop ((operands (markup-body node)))
(if (null? operands)
#t
(begin
;; no braces
(output (car operands) engine)
(if (pair? (cdr operands))
(display " - "))
(loop (cdr operands)))))))
(define-macro (simple-lout-markup-writer sym . lout-name)
`(markup-writer ',(symbol-append 'eq: sym)
(find-engine 'lout)
:action (lambda (node engine)
(let loop ((operands (markup-body node)))
(if (null? operands)
#t
(begin
(display " { ")
(output (car operands) engine)
(display " }")
(if (pair? (cdr operands))
(display ,(string-append " "
(if (null? lout-name)
(symbol->string sym)
(car lout-name))
" ")))
(loop (cdr operands))))))))
(simple-lout-markup-writer * "times")
(simple-lout-markup-writer / "over")
(simple-lout-markup-writer =)
(simple-lout-markup-writer <)
(simple-lout-markup-writer >)
(simple-lout-markup-writer <=)
(simple-lout-markup-writer >=)
(markup-writer 'eq:expt (find-engine 'lout)
:action (lambda (node engine)
(let ((body (markup-body node)))
(if (= (length body) 2)
(let ((base (car body))
(expt (cadr body)))
(display " { { ")
(if (markup? base) (display "("))
(output base engine)
(if (markup? base) (display ")"))
(display " } sup { ")
(output expt engine)
(display " } } "))
(skribe-error 'eq:expt "wrong number of arguments"
body)))))
;;;
;;; Sums, products, integrals, etc.
;;;
(define-macro (range-lout-markup-writer sym lout-name)
`(markup-writer ',(symbol-append 'eq: sym) (find-engine 'lout)
:action (lambda (node engine)
(let ((from (markup-option node :from))
(to (markup-option node :to))
(body (markup-body node)))
(display ,(string-append " { big " lout-name
" from { "))
(output from engine)
(display " } to { ")
(output to engine)
(display " } { ")
(output body engine)
(display " } } ")))))
(range-lout-markup-writer sum "sum")
(range-lout-markup-writer product "prod")
(markup-writer 'eq:script (find-engine 'lout)
:action (lambda (node engine)
(let ((body (markup-body node))
(sup (markup-option node :sup))
(sub (markup-option node :sub)))
(display " { { ")
(output body engine)
(display " } ")
(if sup
(begin
(display (if sub " supp { " " sup { "))
(output sup engine)
(display " } ")))
(if sub
(begin
(display " on { ")
(output sub engine)
(display " } ")))
(display " } "))))
;;;
;;; Text-only implementation.
;;;
(markup-writer 'eq (find-engine 'base)
:action (lambda (node engine)
(output (apply it (markup-body node)) engine)))
(markup-writer 'eq:/ (find-engine 'base)
:action (lambda (node engine)
(let loop ((operands (markup-body node)))
(if (null? operands)
#t
(begin
(display " ")
(output (car operands) engine)
(display " ")
(if (pair? (cdr operands))
(display " / "))
(loop (cdr operands)))))))
;;; arch-tag: 58764650-2684-47a6-8cc7-6288f2b474da
;;; eq.scm ends here
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